Philip Glass’s “Madrigal Opera,” which received a rare performance at National Sawdust on Saturday, could have been born from a similar question. The hourlong work has no plot, no characters and no libretto, but features six singers, a violin and a viola. Can a composer still build an opera with them?

In principle, yes. Whether the result still tastes like an opera should remain a subject for debate.

What it sounds like is easier to answer. In the weightless reading by the violinist Johnny Gandelsman, the violist William Frampton and the vocal ensemble Choral Chameleon, the music unfolded in contemplative beauty, with the juxtaposition of the instruments’ throaty individuality and the even-tempered coolness of the voices creating just enough tension to sustain interest.

Photo

William Frampton, on viola, performed with Choral Chameleon in “Madrigal Opera.”Credit
Caitlin Ochs for The New York Times

The music consists of a pointillist choral score over undulating arpeggios played on the violin in the first half of the piece, then on the viola. Streams of repeated motifs swirl and settle in ever new harmonic configurations like a murmuration of starlings. The singers intone the note names from the solfège system, creating a perfectly closed system of medium and message. You could say that the text determines the music, or that each note dictates the syllable that will convey it: Both statements are equally true. As such the work is both completely transparent and reveals nothing.